Why Big Teams Suck: Seven (Plus or Minus Two) Is the Magical Number Once Again

I also posted this piece over at LinkedIn this morning. It offers a simple lesson, but one that is often disregarded, and in turn undermines the team and organizational performance, creates dysfunctional conflict. and weakens social bonds.

In 1957, British naval historian and management satirist Northcote Parkinson painted a cynical picture of a typical committee: It starts with four or five members, quickly grows to nine or ten, and, once it balloons to 20 and beyond, meetings become an utter waste of time – and all the important work is done before and after meetings by four or five most influential members.

As Parkinson would have it, numerous studies now confirm that, when it comes to teams, many hands do not make light work. After devoting nearly 50 years to studying team performance, the late Harvard researcher J. Richard Hackman concluded that four to six members is the team best size for most tasks, that no work team should have more than 10 members, and that performance problems and interpersonal friction increase “exponentially as team size increases.”

These troubles arise because larger teams place often overwhelming “cognitive load” on individual members. Most of us are able to mesh your efforts with and maintain good personal relationships with, say, three or four teammates. But as a group expands further, each member devotes more time to coordination chores (and less time to actually doing the work), more hand-offs between the growing cast of members are required (creating opportunities for miscommunication and mistakes), and because each member must divide his or her attention among a longer list of colleagues, the team’s social glue weakens (and destructive conflict soars). Following this LinkedIn piece, findings about group size are reminiscent of psychologist George Miller’s famous conclusion that seven was a “magical number” because people could only hold “seven, plus or minus two” numbers in short-term memory. Both Hackman and Miller found that, once people start trying to deal with double digits, the cognitive overload takes a toll.

These findings help explain why the average restaurant reservation in the United States is for a party of four. Think of the last time you were at a dinner with a group of 10 or 15 people. It is difficult, perhaps downright impossible, to have a coherent and emotionally satisfying conversation that engages each member of the party all at once. Typically, the group breaks into a series of smaller conversations or a few people do all the talking and the others say little or nothing.

Some organizations learn about the drawbacks of oversized groups the hard way. Retired Marine Captain and former U.S. Senator James H. Webb explained why the “fire team” – the basic combat fighting unit – shrunk from 12 to 4 during War II. Webb wrote in the Marine Corp Gazette that this “12 man mob” was “immensely difficult” for Marine squad leaders to control under the stress and confusion of battle. Coordination problems were rampant and close relationships – where soldiers fight for their buddies – were tougher to maintain in 12-man teams. The U.S, Navy Seals have learned that four is the optimal size for a combat team as well. And, the basic work unit at McKinsey, the consulting firm, is one “engagement manager” and three other members. As Intuit’s CEO Brad Smith puts it, when it comes to teams, “less is often best.” Just like on­line retailing giant Amazon, Intuit insists: “Our development teams can be no larger than the number of people who can be fed by two pizzas,” which helps them “stay nimble and make decisions quickly.”

This lesson applies to small organizations too. Pulse News, makers of a “news aggrega­tor” app, was started in mid-2010. Communication breakdowns and misunderstandings flared-up after it grew slightly, from three to eight people. Founders Akshay Kothari and Ankit Gupta told us that, after they divided those eight among three teams, people produced better software, did it faster, and argued less. When Pulse expanded to about 12 people (working in four teams, all in the same room), each team maintained a bulletin board that captured their current work to help everyone at Pulse follow what they were doing. Every afternoon at about 3:30, each team also gave a short talk to the company about what they working on and where they needed help. Pulse relied on small teams as it grew to 25 employees and 30 million users; it is now part of LinkedIn, which bought Pulse for 90 million dollars in April, 2013.

The lesson is that, if you are on a big team that keeps screwing up, where members don’t care much about each other, and are fighting like crazy, try some subtraction or division. A Harvard Business School study by Melissa Valentine and Amy Edmondson of a large hospital’s emergency department demonstrates how powerful such moves can be. The crowd of 30 or so doctors and nurses who staffed the department at any given time were divided into multiple six person “pods,” each led by a senior doctor or “attending physician.” After the change, information about patients flowed more quickly and accurately and personal relationships improved markedly. Smaller teams reduced confusion and discomfort about who to ask for help and updates.

One nurse said, before the pods, “You had to walk across the ED all timid” and get up bit of courage and say to the doctor “Uh, excuse me?” With the pods, “Now they are in the trenches with us.” It was also easier to discern which “podmates” were responsible for particular chores and deserved credit or blame when things went well or badly.

Another nurse added:

“Now there is much more of a sense of ownership of each other. I’ll say, “My pod isn’t running well. Where is my doctor?” And he’ll be accountable to me. And the doctors will say, “Where are my nurses, who do I have today?’” People rarely, if ever, claimed each other in this way before the pods were implemented even if they were working together on many shared cases. A resident would have used more detached language like, “Who is this patient’s nurse?” – ignoring that the nurse had any relationship to him – rather than, “Where are my nurses?”

The pods also created big efficiency gains. Valentine and Edmondson analyzed data on 160,000 patients served by the Department during the six months before the pods were created and the year after. After the pods, patient throughput time plummeted by about 40%, from about eight hours (8.34) to five hours (5.29) per patient –without increased staffing levels. This drop not only reflects more efficient use of staff; think of the patients’ experience: Five hours at the hospital sucks a lot less than eight.

The upshot? As my co-author Huggy Rao and I found in our research, scaling is a problem of both more and less. Many hands do not always make for light work, especially when it comes to team size. The first question I ask when a team reports they are locked in dysfunctional conflict, suffering from indifference, making bad decisions, or missing deadlines -- or all of the above -- is “how big is it?” If the answer is more than then five or six members, especially more than than ten, some savvy subtraction or division can create striking improvements. As Valentine and Edmondson's research shows: Leaders become more effective. Efficiency improves. Interpersonal friction wanes. And strangers become friends.

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Great article to remind us of the 7(+/-2) axiom. We had a project recently with close to 20 engineers. We broke the team up into 4 teams: Firmware, FPGA, Hardware, and sort of steering team that managed the coordination with the development teams and Ops/Management/Finance. It worked well. As I read your article I realized our division followed the 7(+/-2) rule. We didn't consciously follow the rule. But your article is illuminating and next time, I'm sure we'll be more conscious of it. Thanks!

This isn't news. In 1920, Lord Robert Baden-Powel consolidated notes he had assembled on the training of boys through Scouting and published them as Aids to Scoutmastership. He wrote,

"The Patrol System is the one essential feature in which Scout training differs from that of all other organisations, and where the System is properly applied, it is absolutely bound to bring success. It cannot help itself!

The formation of the boys into Patrols of from six to eight and training them as separate units each under its own responsible leader is the key to a good Troop.

The Patrol is the unit of Scouting always, whether for work or for play, for discipline or for duty. An invaluable step in character training is to put responsibility on to the individual. This is immediately gained in appointing a Patrol Leader to responsible command of his Patrol. It is up to him to take hold of and to develop the qualities of each boy in his Patrol. It sounds a big order, but in practice it works. Then, through emulation and competition between Patrols, you produce a Patrol spirit which is eminently satisfactory, since it raises the tone among the boys and develops a higher standard of efficiency all round. Each boy in the Patrol realises that he is in himself a responsible unit and that the honour of his group depends in some degree on his own ability in playing the game."

It's still true for boys and girls, and it's also true for adults. People can work more effectively in groups of five to nine.